‘We can tend to gardens as acts to mitigate climate and foster biodiversity. But we can also challenge the relationships that have brought these particular gardens into being’
Photograph: Peter Hobbs

The clematis is in full bloom right now: a riot of purple flowers up the side of the deck, aiming for the wall.

Being a vine, a clematis will twine around anything that crosses its path, including itself, at all available opportunities. The result is often, even with a short period of gardener inattention, a snarly mess; the leafstalks curl, and curl, in on themselves in order to find some – any – purchase. In this situation, if you want to coax the vine outward, you have to unwind the intricate tendrils very gently and place them against better climbing scaffolds: a thin stick, a wire. One long Canadian spring afternoon in May, that is what I did: slowly and carefully took apart the knots, suggesting to each shoot a less tangled path up a new, metal trellis.

On that particular afternoon, I had to wait until the sun had passed over the deck to do this work, or it would have been just too hot. It was nearly 31C that afternoon with high humidity: not quite record-breaking, but unseasonable for Toronto. Summers, here, are getting longer and hotter, and winters warmer and more unpredictable. This year, the thermometer hit 16C in February: that’s in a Canadian city in which the historical average high for the month is -3C. Now, we are in the middle of an extended heatwave.

In a year of large contrasts, there was also an exceptional storm in mid-April that turned roads and sidewalks to glass for days, and with such high winds that insurance companies threw up their hands at the number of claims related to roof damage, including mine. Then in May – May! – there was a heat alert. This is enough drama to make even my least environmentally-conscious friends make noises about global warming.

The garden has suffered this year, especially the lower-growing plants; even some of the hardy, well-established lavenders packed it in. The problem is not that it was too cold (although there was a top-10 longest and coldest polar air event in December/January), or that it was too warm in those double-digit February days, or that there was the ice storm in April, or that it was 31C in May, or even that there are now again record-breaking temperatures. The problem is that all of these things happened in a remarkably short time span, and that longer-term climate changes have already begun to destabilise plant communities, making them more vulnerable to extreme weather events.

What can I do, concretely, to mitigate change, to adapt to it, and even to resist it?

From my perspective as caretaker of this little plant community, the problem is also that many of the seasonal understandings that have been basic to gardening in Toronto can no longer be assumed. Lavender might not survive the winter without wrapping. Tomatoes might need to be shaded in order to survive what is forecast to be an especially hot summer. Plants that require specialist pollinators may find their calls unanswered because the short-lived insects on which they rely may now have lives out of sync with the blooms.

There is a multitude of opinions about gardening in these climate changing times. Many urban gardeners talk about how to protect their plants from climate change: shielding them from extreme temperatures, conserving and/or diverting water, planting a greater range of resilient species in more cohabitative arrangements, and being extra-aware of the presence of both predatory and pollinator insects.

Some gardeners understand their work as itself a form of climate change mitigation: getting rid of lawns that require mowing, planting to preserve and foster biodiversity, moving toward organic and permaculture practices to decrease the use of chemical fertilisers, and favouring native species that know what resilience means. Some are preparing for an intensified food security crisis, adapting flower beds for vegetables, and planting fruit-bearing shrubs and trees for future sustenance.

To me, more than anything, gardening in these times means two things. First, looking after my little backyard demands that I pay close attention to the present and future: what are the plants telling me about the ways the climate is changing? What do they need that I can give them? What do these needs tell me about the larger scale of the changes in which we are immersed? What can I do, concretely, to mitigate change, to adapt to it, and even to resist it?

Second, and more foundationally, this garden invites me to reflect on the past and present: on gardening itself, and how the particular plants I am tending are part of larger processes of colonial, global transformation in which histories of plant movements are bound up with those of capitalist, fossil-fueled developments. We can, perhaps, more easily think about cotton, wheat, sugar cane, and corn at this level: plants that were central to slavery, to the rise of industrial agriculture, to what some scholars call “ecological imperialism.” But gardens are also part of this picture.

Think about the clematis, for example. The purple specimen growing up my back deck is a Clematis “jackmanii”, a cross with Mediterranean and Chinese origins of an already global species first made by 19th century English horticulturalist George Jackman. Although there have been clematis in North America for millennia, there is no question that the international spread of C. “jackmanii” stems from a history of British colonial botany and, more recently, capitalist horticultural trade, both of which have selected for masses of large blooms rather than, say, medicinal potency. Many popular cultivars originate from particular species that are appealing to this narrow set of aesthetic criteria. The resulting inbreeding has spread particular diseases, like “clematis wilt”; moreover, the favouring of these cultivars by gardeners and industry means that less attention is paid to species that invite different kinds of relationship.

What does it mean, then, to worry about this beautiful, compromised, plant in the midst of climate change, when it is already so clearly implicated in global colonialism and capitalism? Yes, we can tend to gardens as acts to mitigate climate and foster biodiversity. But we can also challenge the relationships that have brought these particular gardens into being as part of, rather than as a refuge from, climate changing times. Gardens are microcosms of the complicated relationships that are the difficult world in which we are living, whether we like it or not, even as we may consciously refract those relations into new possibilities. In the garden, this practice involves taking careful stock: of the plants that are here, of the travels that have brought them here, and of the possibilities that “here” might yet bring about.

• Catriona Sandilands is a professor in the faculty of environmental studies at York University, Toronto